include/vlc_viewpoint.h

   1 /*****************************************************************************
   2  * vlc_viewpoint.h: viewpoint struct and helpers
   3  *****************************************************************************
   4  * Copyright (C) 2017 VLC authors and VideoLAN
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifndef VLC_VIEWPOINT_H_
  22 #define VLC_VIEWPOINT_H_ 1
  23
  24 #include <vlc_common.h>
  25
  26 #include <math.h>
  27
  28 /**
  29  * \file
  30  * Video and audio viewpoint struct and helpers
  31  */
  32
  33 #define FIELD_OF_VIEW_DEGREES_DEFAULT  80.f
  34 #define FIELD_OF_VIEW_DEGREES_MAX 150.f
  35 #define FIELD_OF_VIEW_DEGREES_MIN 20.f
  36
  37 /**
  38  * Viewpoints
  39  */
  40 struct vlc_viewpoint_t {
  41     float yaw;   /* yaw in degrees */
  42     float pitch; /* pitch in degrees */
  43     float roll;  /* roll in degrees */
  44     float fov;   /* field of view in degrees */
  45 };
  46
  47 static inline void vlc_viewpoint_init( vlc_viewpoint_t *p_vp )
  48 {
  49     p_vp->yaw = p_vp->pitch = p_vp->roll = 0.0f;
  50     p_vp->fov = FIELD_OF_VIEW_DEGREES_DEFAULT;
  51 }
  52
  53 static inline void vlc_viewpoint_clip( vlc_viewpoint_t *p_vp )
  54 {
  55     p_vp->yaw = fmodf( p_vp->yaw, 360.f );
  56     p_vp->pitch = fmodf( p_vp->pitch, 360.f );
  57     p_vp->roll = fmodf( p_vp->roll, 360.f );
  58     p_vp->fov = VLC_CLIP( p_vp->fov, FIELD_OF_VIEW_DEGREES_MIN,
  59                           FIELD_OF_VIEW_DEGREES_MAX );
  60 }
  61
  62 /**
  63  * Reverse the viewpoint rotation.
  64  *
  65  * It can be used to convert a camera view into a world transformation.
  66  * It will also copy non-rotation related data from \p src to \p dst.
  67  *
  68  * \param dst the viewpoint with the final reversed rotation
  69  * \param src the viewpoint for which the rotation need to be reversed
  70  */
  71 static inline void vlc_viewpoint_reverse( vlc_viewpoint_t *dst,
  72                                           const vlc_viewpoint_t *src )
  73 {
  74     dst->yaw   = -src->yaw;
  75     dst->pitch = -src->pitch;
  76     dst->roll  = -src->roll;
  77
  78     dst->fov   = src->fov;
  79 }
  80
  81 /**
  82  * Generate the 4x4 transform matrix corresponding to a viewpoint
  83  *
  84  * Convert a vlc_viewpoint_t into a 4x4 transform matrix with a column-major
  85  * layout.
  86  * The transformation is applied as-is. you have to reverse the viewpoint with
  87  * \ref vlc_viewpoint_reverse first if you want to transform the world.
  88  *
  89  * \param vp a valid viewpoint object
  90  * \param matrix a 4x4-sized array which will contain the matrix data
  91  */
  92 VLC_API
  93 void vlc_viewpoint_to_4x4( const vlc_viewpoint_t *vp, float *matrix );
  94
  95 #endif /* VLC_VIEWPOINT_H_ */